The present invention relates to the art of producing an image on an imageable surface of a flexible material while the material is held in a cylindrical shape. The present invention specifically relates to an image setting apparatus that retains the material in the cylindrical shape without the use of a conventional full drum.
Within the image setting art, it is known to utilize a hollow interior drum device for the production of an image onto an imageable material. This is commonly referred to as internal drum technology. The drum device has a portion that extends along and about a cylinder axis. The portion is continuous along the cylinder axis, but is open at one segment about the cylinder axis to provide a general xe2x80x9cCxe2x80x9d shape when viewed along the cylinder axis. Imageable material (e.g., photosensitive film or paper) is located inside of the drum device such that the material presses against an inner, cylindrical surface of the drum device. A firm contact against the inner surface is often accomplished via the use of a vacuum system operatively connected to perforations extending to the inner surface. Additionally, various means are also used to counter friction between the drum inner surface and the flexible media. This friction interferes with accurate positioning of the flexible media within the drum inner surface.
A device for exposing the imageable material is located at least partially within the interior of the drum device. For example, the exposing device includes a laser and a rotating reflective member (e.g., a mirror or prism). Light from the laser is directed along the cylinder axis and impinges upon the reflective member, which is rotating on the cylinder axis. The light is redirected onto the imageable material via the reflective member. Rotation of the reflective member provides for a scan across the imageable material and axial movement of the reflective member provides for progression of the scan along the axial extent of the imageable material.
In order to produce a good image, the cylindrical surface must be manufactured to have minimal deviation from an ideal cylinder shape. Manufacture of a unitary drum device that has such a desirous cylindrical surface is difficult and expensive. For example, manufacturing requires a high degree of precise machining accuracy over the entire inner surface. Also, the drum device has a fixed size and tends to be relatively heavy.
It is also known within the image setting art to utilize two or more circular rings or disks to provide for an internal imaging set-up. Specifically, imageable material is tensioned around the plurality of rings to form a virtual internal imaging drum (i.e., the flexible material is held in a cylindrical state). As with the conventional internal drum technology, an inner surface of the imageable material is exposed via the use of a translational/rotational reflective member (e.g., a moving prism or mirror) while the material is in the cylindrical state. However, a certain amount of ring contact with the inwardly-facing imageable surface of the imageable material is necessary. As such, a certain amount of the imageable material is unusable and thus wasted. Also, in one embodiment of such a virtual imaging arrangement, a ring or disk is axially moved along the imageable material while the reflective member is axially moved. However, such a moving ring may cause abrasion against the imageable material.
In accordance with one aspect, the present invention provides an image setting apparatus for producing an image on a flexible section of imageable material. The apparatus includes retainer means for retaining the flexible section in a cylindrical configuration about a cylinder axis, with an imageable surface of the section facing inwardly toward the axis. The apparatus includes means for selectively exposing the inwardly-facing imageable surface to produce the image. The retainer means included a plurality of arced supports spaced from each other along the axis. Each support has a curved surface segment for physical contact with an outwardly-facing surface of the section.